第一性原理研究掺杂过渡元素对碳化钨性能的影响

碳化钨(WC)在高温动力装备上应用越来越多,WC的脆性和高密度限制了其更广泛的使用,金属原子掺杂是提高WC性能的一种方法.采用基于第一原理的广义梯度作为近似交换相关函数,研究了A0.25W0.75C(A为Ti、V、Cr、Mn、Co和Ni)的弹性、电子和X射线吸收特性.数值分析结果显示,Ti0.25W075C的B/G值(...

First Principle Study on Tungsten Carbide with Transition Elements

Tungsten carbide(WC)is increasingly used in high-temperature power equipment.The brittleness and high density of WC restrict its wider use.Metal atom doping is a method to improve the performance of WC.The generalized gradient based on the first principle was used as the approximate exchange correlation function.The elastic,electron and X-ray absorption characteristics of A_0.25W_0.75C(A is Ti,V,Cr,Mn,Co and Ni)were studied.According to the numerical analysis,the BIG value of Ti_0.25W_0.75 c(B is the volume modulus,G is the shear modulus)is 1.869,the material is the modified ductile material,and others are brittle materials.The brittleness of WC decreases with the doping of 25%V,Co and Ni atoms,and brittleness increases with the doping of 25%Cr and Mn atoms After doping,the range of density of state decreases,the value of Fermi level increases,and the metallicity of the compounds increases.Among them,Mn_0.25W_0.75C has the strongest metallicity.The X-ray absorption spectrum shifts blue after doping,and there is an absorption band in a soft X-ray band.The strong absorption peaks appears in the 15.7422.25 nm band after doping Cr,V,and Ti.The results are helpful to the experimental and application study of WC compounds with plasticity and low density.